How to reset iphone? Reset passcode?

How to reset iphone? Reset passcode?

Give it back to the owner

Plug it into your computer with Itunes and when prompted to enter the password, deny it. There's only one option at this point and that would be to factory restore it, which resets everything to its default empty state.

Basically, your going to have to restore you iPhone which will restore your iPhone to its original factory state (wiped clean like a brand new one) causing you to lose all of your data that is on your phone. Anything not backed up to iTunes or iCloud will be lost, but there isn't anything you can do about it now.

This is the process that you want to follow to restore the iPhone (launching it in Recovery Mode):

1. Launch iTunes on your computer.
2. Connect the USB cord to the computer, but DO NOT connect your iPhone.
3. Turn the iPhone off using the sleep/wak switch at the top.
4. Press and hold down the home button while you connect you iPhone to the computer.
5. Continue holding the home button until a dialog box appears. This is basically just to show that your iPhone is in recovery mode and can't be used with iTunes until it is restored.
6. Inder the Summary tab in iTunes, click on the Restore button. Again, this will wipe your iPhone clean of all apps, music, photos, and other content.
7. Now that your iPhone is restored, you can choose to load the content back onto tour phone through an iTunes/iCloud backup or start from scratch.

That should do the trick!

And if not, there's another option in the link below.